Side by side these images appear not too dissimilar when looking at the subject matter. When you look at the background however, things are very different.
Using the same lens (Canon EF 75-300mm, I took the first photograph at the full 300mm (distance approx. 15ft.). I then moved towards the subject, zooming out the closer I went to maintain the same image composition where possible. I then took the same photo again, but this time at 75mm. The aperture and shutter speed were set at f/16 & 1/60sec. for both shots.
Comparing both images it can be seen that the most noticeable difference is the amount of background information which is included in the second image. The first image is really compressed and all sense of depth is lost. So too is the amount of definition, suggesting that this set-up is much better suited to portraiture, although there are much better lenses than this ‘long’ lens (somewhere between 50mm – 85mm would be better.
The right hand side of the image is particularly interesting insofar as the cropping point is identical (+/-) for both the boy and the house. Yet because of the compression between the two subjects the background has become bigger whilst the subject remains the same size! This distortion of perspective can be best replicated with the use of a lens of about 50mm, in conjunction with a full frame camera, or 33mm with a cropped frame camera.
I see! 